Supporting, cooling, and lubricating means for high-speed shafts or spindles



Patented July 9, 1940 SUPPORTING, COOLING, AND LUBRICATING MEANS FOR.HIGH-SPEED SHAFTS OR SPINDLES Mario Consigliere, Genoa-Nervi, Italy inDecember 17, 1930, Serial No.- 240,475

In Italy December 21, 1937 s 6 Claims. (01. 51 -166) This inventionrelates to anv apparatus for Applicatio grinding small bores.

It is known that the grinding of small bores -still meets withdifflculties the first of all being 6 the high angular speeds requiredfor such work.

In fact, for a good production and a careful finishing it is necessarythat the peripheral speed of the grinding tool be kept between 20 and 30metres persec. For instance, for grinding a bore having a diameter of 6mm. by using a grinding wheel having a diameter of 5 mm.. by aperipheral speed of 25 m./sec., the angular speed of the tool must reach100,000 revs. per min. Further, if the bore has a considerable depth,and at present such depth equals in many instances ten timesthe'diameter of the bore, it isnecessary to employ very long and finespindles. Always considering a bore of 6 mm. the spindle should have forsuch depths a length of. about 60 mm. and adiameter of not over 4 mm. inorder to bear at its end a grinding wheel having a diameter of 5 mm.When considering that the total amount of overhanging from thebearingcould not be less than 70 mm. the theoreticalcritic speed of sucha spindle would be of 34,000 revs. only, i. e. almost one-third of theangular speed required for agood operation of the grinding wheel.

ing from those now in use, fully answers the different requirements thatI am going to shortly carrying spindle driven at very high speeds, havepoint out hereinafter.

The rotating part must be very light guided by multiple bearings andhave a modulus of resistance that is higher than thatv overhangingrotating-solid spindles now in use.

Fll

rther it is the bearings.

Such problems and still some other ones connected with the constructionof devices for-the grinding of small bores having a grinding wheelbeenbrilliantly resolved in the manner thatshall clearly a'ppearfrom apractical embodiment which is shown by way of a non-limiting example inthe annexed drawing, in which:

Fig. 1. is an axial section of the forepart of a spindle for grindingsmall bores, based principle of the present invention;

upon the Fig. 2 1st. reduced section of the rear part 01' same spindle;I

Fig. 3 is a front view on enlarged scale of the same spindle. a

The spindle shown in the drawing is designed for the grinding of smallbores. It is known that as a grinding wheel must have a peripheral speedof 20 to 30 meters per sec. and when grinding bores having a diameter ofless than 1 cm., by employing a grinding wheel having a diameter ofsay 5mm., the spindle must turn at 100,000 revs. p. min.

At such an exceedingly high speed, and even at a substantially lowernumber of revolutions, it is practically impossible to provide for an 3efilcient cooling by the ordinary means. and also the lubricationappears practically impossible by the usual means, as an oil film of acertain thickness practicallyacts as insulating means and being stronglylaminated contributes towards an increase of'friction.

According to the present invention the above inconveniences areovercomeas follows:

At least one of the rotation bearings of spindle V and in this instancethe outer end bearing X of the shaft, has a perfectly adjustableclearance and is provided with longitudinalgrooves, through which acurrent of cooling fluid having leached the parts rotating at high speedis discharged.

Said fiuid, generally consisting of compressed air, isconvenlently oiledor otherwise greased,

before it reaches. the rotating parts, by causing it to pass through afelt, pad F or other porous diaphragm imbibed with oil or likelubricating means. In the present instance the imbibing of felt F withoil is obtained by causing a part of said felt to dip'into an oilchamber I3.

, By way of example I am going to describe in the following an improvedtool for the grinding of small bores, constituting a considerableimprovement-over all like tool and embodying the above principles,though it' is understood that the same system can apply to any toolhaving -a spindle or shaft, driven at high speed either by a turbinewheel, as in the present instance,

.. block I is slidably mounted. The block I has at its periphery anumber of axial grooves which, together with the adjacent walls ofeasing H,

define conduits 5 m the passage of fluid.

In the fore part of block I a turbine wheel 0 is mounted, having aprojecting hub 6 mounted on convenient bearings N-N' acting as rotationand thrust bearings. Hub 6 is axially bored and extends through thebottom of a cup-shaped part M abutting on oneside against the outer raceof bearing N and on the other side against a screw threaded axiallybored disk. L, through which therefore the axial position of bearingsN-N' may be registered. Block I is fitted at its outer end with anannular disk P carrying nozzle 1 in communication with air duct andarranged in such a manner as to discharge the air through the turbinewheel 0 and to enact on the latter an inward thrust, in the directionof. bearings N-N. The outlet of air from the turbine wheel to theexterior is effected through chamber 8 of block I and port 9 of easingH.

To the outwardly projecting threaded hub part 6' of turbine wheel 0 thespindle V is fitted by means of an inwardly flanged nut T, bearingagainst the abutment washer 10 of spindle V. Spindle V is rotatablyfitted in bearings U and X. Bearing U is fitted within a cavity offianged disk member H having as outer central extension the supportingsleeve W. This sleeve is bored axially, but in the present case, where aboring spindle is concerned, an eccentric bore, as shown in Figs. 1 and3,.should be preferred. The outer end of the spindle bore is flared toreceive the plug-like outer bearing X having, like the correspondingouter part of the spindle a preferably conical bore and is provided withlongitudinal or also helical (Gleason) grooves to enable the refrig- Iblock I can be registered by means of screw-shaft D under theaction of aspring C, and which'cari be shifted axially along the outer annularchamber ofcasing H by means of a screw-sleeve l2, abutting against aplug-like closure member E fitted to the end of casing H. a

By the axial shifting of the shaft D and of the block I, the position ofspindle V within its supporting sleeves W can be registered. Inconsideration of the fact; that the outer end of the spindle is conical,it is apparent that by; axial shifting of said sleeve the clearancespace between the outer end of spindle V and its bearing X can beexactly registered. a

The annularchamber I1 is filled at its lower part with oil. This chamberis formed by insert- .ing co-axially with casing H a pair of flangedsleeves I l-I4; between which afelt pad, F is inserted, so as to dip inthe oil of chamber l1. Sleeve H is fittedon an air-inlet nipple G onwhich a-pressure spring 'A is arranged.

A portion of the pressure air is led through port IS in the upper partof chamber I1, and

-is cooledand deposits any eventual excess of oil.

A part of said oiled air is discharged through the axial bore of hub 6of the turbine wheel and the axial 'bor 2| of the first part of spindleV and cross bores 22 of said spindle. From said cross bores it isdischarged between the spindle V and its supporting sleeve W leachingthese parts throughout their length and is led out through thelongitudinal grooves of bearing X and cools the grinding wheel Yandblows out the dust of grinding.

Another portion of the air from chamber 20 is led through a filterthrough the bearings N-N' and to the exterior through part 9.

Due to the :fact that this air does not carry an excess of oil, thegrinding wheel and other rapidly rotating parts do not becomeexceedingly work is performed more facility spindle. V and sleeve W, aswell as to angularly adjust sleeve W in connection with the nature ofwork to be performed, all due to the above described mounting.-

- From the preceding it is' 'apparent that the new spindle represents asubstantial improvement over the tools of this kind hitherto known.

in fact, due to the improved construction and arrangement of the partsand especially-of the turbine wheel and to the cooling and lubricatingmeans, angular speeds as high as 100,000 R. P. M. and more are possible,while keeping the working parts substantially cool.

It is also apparent that'the present invention is not confined to thespecial construction here illustrated by way of anexample.

- I claim: f

1. An abrading tool comprising in combination: one casing, a blockslidably arranged upon said casing, a turbine wheel having an axiallybored hub fitted within said block and rotatably mounted on rotationandthrust bearings; a nozzle carrying disk fitted at the end of saidblock, with noazle blowing against the turbine wheel, a dischargechamber provided within said sliding block and in communication with anoutlet port of said casing, a spindle having abutment means mountedwithin the end of the bore of the turbine hub, a screw-threaded flangednut coacting with the turbine wheel hub. and abutment means of thespindle, for keeping the spindle in position; a flanged disk fitted atthe end of said casing, an overhanging sleeve member integral with saiddisk and projecting outwardly, through which the outer part of thespindle is passed, a

pair of bearings for the spindle at both ends of said sleeve, groovescut through the inner surface of the outer'bearing, an air duct axiallytraversing the rear part of said spindle and with a' transverse openingnear the inlet end of saidoverhanging sleeve; means for feeding pressurefluid to the turbine wheel and means for feeding -oiled air through theturbine bearings and along the bore of turbine hub, from the rear partof spindle, as well as along the sleeved outer spindle surfaces and,through the grooves of the outer bearing, against the abrading ,orgrinding ,wheel.

3. An'abrading tool according to claim 1, in

which the outer end of the spindle and its bearing are conical andcomprising further means for enacting an axial sliding of thespindle-carrying block; means for shunting one part of the air admittedto the turbine wheel through an oiled pad; an expansion chamber for theoiled- 4. An abrading tpol comprising in combination an action turbinewheel mounted on rotation and thrust bearings; means for feeding air tosaid turbine wheel so as to rapidly rotate same as well as to impress onthe same an axial thrust in the direction of the thrust bearings;. aspindle fitted on said turbine wheel, bearings at the ends of saidspindle, means for feeding oiled air through those parts of the turbinewheel bearings extending along the spindle and between the spindle andits end bearing, an eccentrically bored, overhanging sleeve enclosingand stiffening the overhanging part of the spindle; a grinding wheelfitted at the free end of said spindle and a screw keeping this grindingwheel in place.

5. An abrading tool, according to claim 4, wherein an outer casing'isprovided and divided into two co-axial longitudinal sections, one ofwhich containingthe ducts for the admission of air, and the other themeans for axially register- -ing the turbine wheel and spindle carryingblock as well as an oil-reservoir and a pad inserted in the said oilreservoir and extending through the passages for the cooling air to beoiled for lubricating purposes. 7

6. An abrading tool according to claim 1 which pressure through a padconstantly imbibed with oil.

MARIO CONSIGLIERE.

further comprises means for leading air under

